Preheating for shear studs?

[bridgebuster]

Is preheating necessary when using a gun to weld shear studs? AWS D1.5 (2005) doesn’t require preheating. However we have a project that requires preheating in accordance with Table 4.4.

The contractor doesn’t want to preheat because it’s damaging the paint system and causing some localized buckling of the stay-in-place forms. The stud manufacturer says preheating is unnecessary and the DOT never enforces this provision.

Years ago when I worked as a construction inspector no one used preheating for studs and we never had a major problems. There was the occasional partial flash but that was it.

Any thoughts?

 

[metengr]

Depends on the substrate material chemical composition that will hold the stud, and the function of the stud.

For non-hardenable grades of ferrous and nonferrous materials preheat should not be required. For hardenable grades of steel preheat may be required based on the size and function of the stud itself. For example, non-loading bearing studs that are attached by a stud gun using short arc or resistance welding typically does not require preheat.

 

[bridgebuster]

It's A709 Gr. 50; rolled beam with 1 3/4" flanges.

 

[metengr]

Based on the material states, I really don't see a need for specific preheat unless the stud welding is being done where the metal temperature is below 50 deg F.

 

[bridgebuster]

Thanks